The present invention relates generally, to an apparatus and a method for separating heterogeneous mixtures of at least two components. These mixtures could be immiscible liquid/liquid solutions as in separating oil from water, or solid/liquid mixtures as in separating solid waste from sewage water.
There are many different areas of industry that require the separation of heterogeneous mixtures. These mixtures are usually separated either for recycling or during waste disposal. In most cases there are requirements as to fluid purity, and recycling and construction costs. These requirements arise from many different sources, including increasing federal and state regulation of industrial and city waste water purity. This increased regulation creates a need for improved methods of separating solid wastes from waste water. Industries that utilize solvents or fluids as transport media find it increasingly economical to recycle the solvents and transport media. This is necessary to keep local aquifers and streams clean and pristine. As our culture becomes more and more environmentally conscious, the purity of fluid output increases. Even within nominally non-polluting industries there is a need for improved separation of particles and solvents from manufacturing techniques.
Prior solutions to this separation need have concentrated upon controlling any turbulence created upon injection of a waste fluid into one end (influent) of either a rectangular or a cylindrical separation tank and removed at an opposite end (effluent). The waste fluid flows from the influent end of the tank to the effluent end in either a laminar flow upon a separation field or in a slow moving bulk flow of the waste through baffles designed to aid in separation.
U.S. Pat. No. 1,672,583 issued to Travers on Jun. 5, 1928 is a device that consists of a tank with vertically offset baffles. These baffles are alternately offset from a bottom and top of the tank respectively. This allows the slow moving bulk solution of immiscible components with differing densities to separate and form a layer between the top and the bottom of the tank. The slow moving fluid travels first under then over alternate baffles. The top baffle acts as a skimmer preventing the less dense material from proceeding along the tank. As the slow moving nonturbulent or quiescent fluid travels under the next baffle it further separates at the surface contiguous with the next adjacent skimming baffle. The number of baffles and flow velocity of the fluid through the separator tank control purity.
U.S. Pat. No. 2,118,157 issued to Camp on May 24, 1938 discloses a method and apparatus for separation of particulate matter in a bulk flow separator tank. This invention allows the fluid to flow with sufficient velocity such that the denser particulate matter settles onto movable floor plates. These floor plates are mounted at a slight incline transverse to the separator tank on a movable means that aid in the transport of any resulting sludge to a disposal trough, or launder.
U.S. Pat. No. 3,419,145 issued to De Celis on Dec. 31, 1968 discloses vertical longitudinally mounted baffles in a large tank that direct the influent in an evenly distributed path along a flow direction. The fluid then flows along the separator tank into a set of exit transversely mounted offset baffles of a type similar to those disclosed by Travers. Finally the effluent is drawn off. The baffles at the influent end greatly reduce any turbulence due to influent influx, and the offset baffles at the effluent end are a final purification step before effluent removal. A combination of influent baffles, fluid flow velocity, and effluent baffles controls separation.
U.S. Pat. No. 4,257,969 issued to Thies on Jun. 12, 1979 addresses the separation of immiscible liquids in a cylindrical separator tank containing transversely mounted vertical baffles. The influent enters the tank at the top and is slowly forced through ports in the central portion of the baffles. The effluent is then drawn off at the bottom of the tank, and the separated fluid or emulsion is drawn off from various ports located at different positions at the top of the tank. The slow introduction of the influent coupled with the baffles effectively reduces turbulence and aides in separation of the different components.
U.S. Pat. No. 4,417,988 issued to Cordoba-Molina et al. on Nov. 29, 1983 addresses a final bulk flow solution. This invention creates an apparatus by mounting a flow constricting device at the effluent end of a bulk flow separator tank. This flow constricting device reduces internal waves or turbulence resulting from the flow of the waste fluid along the tank.
There have been turbulent solutions to separating particulates from a mixture in a bulk flow apparatus. U.S. Pat. No. 1,510,809 issued to Sweetland on Oct. 7, 1924 discloses a method and apparatus whereby addition of a flocculating agent and aeration removes the particulates found in mixtures such as unrefined sugar. Air bubbles trap the particulates and force them to the top where they are subsequently skimmed off. The effluent is then removed from the bottom of the tank.
Those practiced in the art recognize that laminar flow of heterogeneous solutions promote stable flow conditions and lead to a high degree of separation. U.S. Pat. No. 4,957,628 issued to Schulz on Sep. 18, 1990 teaches us a laminar flow solution to the separator tank problem. This invention is a tank whereby the influent enters a tapered trough mounted along a side of the separator tank. The influent then enters the separator tank through a variety of ports located in the side wall and is then directed in laminar flow between inclined transversely mounted plates. These plates are mounted on means such that the degree of inclination may be varied. A movable floor in a manner similar to the Camp patent of 1938 provides means for removal of any resultant sludge.
Finally, U.S. Pat. No. 5,266,191 issued to Greene et al. on Nov. 30, 1993 reveals a device in which the waste fluid flows along closely spaced longitudinally mounted plates. The close spacing of the plates promotes stable laminar flow and improved separation. Greene also provides for a serpentine path along which the waste fluid travels thus increasing separation time and improving purity of the resultant effluent.
All of these solutions require that the influent enter the separator at an end that is opposite the effluent removal end, with the exception of the Schulz patent in which the influent enters a trough that redirects the flow through ports mounted along a side wall. It would be useful to have a separator designed such that the influent enters on the same side that the effluent exits. This will aid in ease of maintenance and reduce construction costs. There is also a great amount of turbulence as the waste fluid enters the separator, meaning no appreciable separation of the components before they enter the separator tank proper. There is a great need for a device that provides for a certain amount of pre-separation before the influent enters the separator proper.
An object of this invention is to provide an apparatus and a method for which heterogeneous solutions may enter the apparatus at the same end at which the effluent is removed and in which an amount of separation occurs prior to the formal entrance to the separator tank. The tank geometry and structure are such that liquid/liquid solutions as well as solid/liquid solutions may be separated. The geometry and structure of the tank are also such that there is significant reduction in flow turbulence, laminar flow is utilized, and significant performance degradation in the purity of the resulting effluent are not seen as fluid flow continues.
A broad object of the present invention to provide a suitable method and apparatus for the separation of at least two component solutions with differing densities.
A further object of the present invention is to provide a method and apparatus for the separation of at least two component solutions with differing densities.
Another object of the present invention is to provide a method and apparatus for the separation of particulates from solution.
A still further object of the present invention is to provide a method and an apparatus with a coalescence chamber to enhance separation prior to entrance of the waste fluid into the separator proper.
A further object of the present invention is to provide a method and an apparatus that utilize baffles attached to corners of the coalescence chamber to aid in coalescence and reduction of turbulence in the influent.